Vocal learning by songbirds provides a model for studying general mechanisms of sensorimotor learning with particular relevance to human speech learning. For both songbirds and humans, hearing the sounds of others, and auditory feedback of oneself, plays a central role in vocal learning. Moreover, both song and speech learning are subject to critical periods: appropriate experience in early life is necessary for normal vocal learning and lack of that experience can lead to permanent deficits in nervous system function. Our previous work suggests that a basal ganglia-forebrain pathway participates in processing auditory feedback and in driving experience-dependent changes to vocalizations. Here, we propose to use a new approach to directly investigate at a behavioral and neural level how auditory feedback contributes to learning and production of songs. We will use systematic manipulations of auditory feedback to characterize more precisely how song behavior depends on hearing (Aim 1). We will couple feedback manipulations with chronic neural recordings from awake behaving birds to determine the nature of signals elicited by altered feedback in vocal control structures (Aim 2). We will also use song-triggered microstimulation of these same structures to test their functional influence on song production and song plasticity (Aim 3). Songbirds provide a system where the influence of performance-based feedback on a well-defined and quantifiable behavior potentially can be understood at a mechanistic level. Such an understanding will provide basic insight into normal learning processes and contribute to our ability to prevent and correct disabilities that arise from dysfunction of these processes. [unreadable] [unreadable]